<!DOCTYPE html>
<html>
<head>
	<meta charset="UTF-8" />
	<title>九宫格-练习1</title>
	<style type="text/css">
		div.container {
			float: left;
			width: 100%;
		}
		div.rectangle {
			float: left;
			background-color: yellow;
			text-align: center;
			width: 30%;
			padding-bottom: 30%;
			margin: 1.5%;
			border-radius: 1em;
		}
	</style>
</head>
<body>
	<div class="container">
		<div class="rectangle"></div>	
		<div class="rectangle"></div>	
		<div class="rectangle"></div>	
		<div class="rectangle"></div>	
		<div class="rectangle"></div>	
		<div class="rectangle"></div>	
		<div class="rectangle"></div>	
		<div class="rectangle"></div>	
		<div class="rectangle"></div>	
	</span>
</div>
</body>
</html>